The present invention relates to liquid formulations, method for their production, and their use as addition to animal feeds and human foods.
The formulation of carotenoids represents a particular challenge because of their slight solubility in water and their chemical instability. There have thus been numerous attempts to provide carotenoid formulations which, on the one hand, are stable and, on the other hand, show good bioavailability and provide the desired color yield on use. Liquid carotenoid formulations are of particular interest because the obtaining of the carotenoids in powder form and the preparation of a liquid formulation by the user become superfluous.
Production of carotenoid primary particles with a particle size in the nanometer range is crucial for achieving adequate bioavailability and color yields. In order to produce such particles, grinding processes have been used in the prior art, as described for example in WO 91/06292 and WO 94/19411. The carotenoids are ground using a colloid mill in aqueous or oily media, achieving a particle size in the nanometer range.
EP 1 460 060 A describes the production of lutein suspensions by grinding in an oil. It also describes cold water-dispersible lutein formulations which are produced by dissolving lutein in a water-immiscible organic solvent and encapsulating in modified starch in the presence of an emulsifier.
US 2005/0084462 describes the production of a color mixture for use in food products, pharmaceutical and cosmetic products by grinding a color in water in the presence of gum arabic as carrier and subsequent heating to 30 to 60° C.
U.S. Pat. No. 5,827,539 describes the grinding of a dispersion of a carotenoid in oil, forming an emulsion with a mixture of starch, sugar and an antioxidant, and subsequent spray drying.
WO 9613178 describes the production of stable lycopene concentrates by grinding lycopene in a liquid medium in which the lycopene is substantially insoluble. The liquid medium used is glycerol, propylene glycol or ethanol. However, a hydrocolloid is not employed.
WO 96/23420 describes the production of oily astaxanthin suspensions with particle sizes of <2 μm by grinding astaxanthin, adding an oil during or after the grinding. The use of protective colloids or emulsifiers is not disclosed. It is pointed out that the particles are prone to agglomeration. Accordingly, further stabilization by storing the suspension below the solidification temperature is considered.
WO 93/04598 describes the production of a carotenoid composition comprising a carotenoid in an oil, a dispersion of a water-dispersible matrix former, for example a sugar, and of a stabilizer, for example gelatin or casein, and an emulsifier and, where appropriate, a non-oily solvent such as glycerol.